1. Technical Field
This invention relates to the field of functionalized olefins. More particularly, it relates to compositions and processes for preparing mixtures of functionalized olefins that may be useful as surfactants or as precursors for preparing surfactants.
2. Background of the Art
Surfactants are widely used in the chemical and manufacturing industries for a wide variety of purposes. These include, for example, imparting wettability and detergency in products including metal cleaning agents, paints, coatings, agricultural spread agents, and the like. The many types of surfactants are generally divided into four general classes—nonionic, anionic, cationic, and amphoteric—each of which offers certain advantages in certain uses. Each type, however, generally includes both a hydrophobic moiety and a hydrophilic moiety. One frequently-employed candidate for the hydrophobic portion of the surfactant molecule is an alcohol.
The value of an alcohol-derived surfactant is heavily dependent upon the characteristics of the starting alcohol. For example, the nature of the alcohol may be determinative of the surfactant's biodegradability, gelling tendency, rate of dissolution in water, and effective cloud point, each of which must be taken into consideration when selecting a surfactant for any given application. Alcohols may be natural or synthetic, but because of practical reasons including cost, product control, and limited availability of natural alcohol sources such as fats, oils and waxes, manufacturers have turned increasingly to synthesizing alcohols with an aim to using them to prepare surfactants.
For example, U.S. Pat. No. 6,963,014 B1 to Zeller et al. describes a process for preparing a C13-alcohol mixture comprising trimerizing a butane-containing C4-hydrocarbon stream containing less than 5 percent by weight of isobutene in the presence of a nickel-containing heterogeneous catalyst; isolating a C12-olefin fraction therefrom; hydroformylating the C12-olefin fraction; and then hydrogenating the product of the hydroformylation. The resultant alcohol mixture may be used to prepare surfactants via processes including alkoxylation, glycosidation, sulfation, phosphation, alkoxylation and subsequent sulfation, or alkoxylation and subsequent phosphation.
Other examples of alcohols synthesized from olefins include the invention represented by U.S. Publication US2004/0133037 A1 to Fenouil et al. This publication describes a process for preparing branched olefins by dehydrogenating an isoparaffinic composition over a suitable catalyst. The isoparaffinic composition is obtained by hydrocracking and hydroisomerization of a paraffinic wax. The produced olefins may be useful for making anionic, nonionic, or cationic surfactants, and in particular surfactant sulfates or sulfonates.
U.S. Pat. No. 6,433,207 B1 to Connor discloses a process for preparing branched olefins involving dimerization followed by an OXO process to form alcohols therefrom. This process claims to eliminate geminal branching, i.e., the elimination of “quaternary” carbon substitution. The resulting alcohols may be further processed to form surfactants.
U.S. Pat. No. 3,887,624 to Gipson et al. discloses vinylidene alcohols having unusually low melting points, that may be prepared by hydroformylation of vinylidene olefins (OXO process), followed by hydrogenation of the product of the hydroformylation. The vinylidene olefins are prepared by conventional dimerization of alpha olefins, mixtures thereof, and the like, such as that described in U.S. Pat. No. 2,695,327. The alpha olefins are prepared from the conventional conversion of ethylene by a combined-growth displacement reaction using a Ziegler-type polymerization catalyst such as a trialkylaluminum catalyst.
While these and a variety of other surfactant-ready alcohols are known in the art, there is still much room for new surfactants representing each of the four surfactant classes. Thus, processes for preparing new surfactant-ready alcohols also continue to be sought, to promote development of new surfactants that may offer improved performance, customization to specific applications, attractive cost, and a high level of environmental acceptance.